The last three years have brought remarkable progress in understanding the disease mechanisms in dominantly-inherited muscular dystrophies, myotonic dystrophy (DM), facioscapulohumeral dystrophy (FSHD), and oculopharyngeal muscular dystrophy (OPMD). A relatively complete pathophysiologic understanding of these disorders is within reach, and it seems likely that more attention will be devoted to developing new treatments. To maximally exploit these research opportunities it will be necessary to expand the base of basic and translational researchers who work on these disorders and give them access to critical biological and bioinformatic resources. To help accomplish this objective, the aim of this project is to develop a Repository Core for the University of Rochester Muscular Dystrophy Cooperative Research Center. The resources in the Repository have been built up over many years by investigators in this Center. These resources include DM and FSHD myoblasts, transgenic mouse models and cells derived from these models, plasmids for expressing expanded RNA repeats and for developing new models for repeat expansion disorders, antibodies, and tissue samples. In addition, a comprehensive database of expression profile data from normal individuals and patients with DM or FHSD will be provided to researchers interested in data mining or to serve as controls for studies of muscle gene expression that are performed at other institutions. Orderly procedures for requesting and delivering materials from the Repository are proposed. By helping to remove barriers to research, this Repository can improve the quality and quantity of research on dominantly-inherited muscular dystrophies, and stimulate the involvement of new investigators.